a b s t r a c tA highly accelerated electronic structure implementation and data mining algorithms have been combined with structural data from the inorganic crystal structure database to generate materials properties for about 22,000 inorganic compounds. It is shown how data mining algorithms employed on the database can identify new functional materials with desired materials properties, resulting in a prediction of 136 novel materials with potential for use as detector materials for ionizing radiation. The methodology behind the automatized ab initio approach is presented, results are tabulated and a version of the complete database is made available at the internet web site (Ref. Sensors, solar cells, advanced batteries, and magnetic strips in credit cards are examples of functional materials present in every-day life. One important task for the research in materials science is the continuous improvement and discovery of new such advanced materials. Ab initio electronic structure calculations as a tool for predicting materials properties have steadily increased in use over the years [2] and play today an important role due to the relatively inexpensive and versatile guidance it offers. There are currently some 8000 studies published annually with this method.Electronic structure theory applied in materials research is typically done in a fashion where a calculation follows, or accompanies, an experimental result. Knowledge on an atomistic level is thus gained which can help in understanding the experimental results [3]. In some rarer cases the theoretical calculations predict a materials property which subsequently may be realized experimentally. An example of the latter is the newly proposed tetragonally distorted FeCo alloy with exceptional out of plane magnetic anisotropy [5,4]. These materials simulations are done in a oneby-one mode, where one calculation accompanies one experiment. However, with an increasing demand of an accelerated speed in finding or predicting new materials this may not be the most efficient approach. Alternatives to this methodology have indeed been discussed, for instance, numerical algorithms which obey evolutionary principles borrowed from biology have been applied to find structural data of compounds and alloys [6], and in a somewhat similar study where formation probabilities derived from correlations mined for in experimental data were used to guide ab initio calculations for unknown structures [7].In this article a method for automatizing the generation of a new database with electronic structure results for a large number (22,000) of inorganic compounds is presented. The necessary structural information for the ab initio calculations is extracted from the inorganic crystal structure database (ICSD) [8]. The electronic structure results are generated within the local density approximation (LDA) of density functional theory (DFT) in combination with a highly accurate full potential linear muffin-tin orbital (FP-LMTO) method [9].We describe how...

Structural studies of biological macromolecules are severely limited by radiation damage. Traditional crystallography curbs the effects of damage by spreading damage over many copies of the molecule of interest in the crystal. X-ray lasers offer an additional opportunity for limiting damage by out-running damage processes with ultrashort and very intense X-ray pulses. Such pulses may allow the imaging of single molecules, clusters, or nanoparticles. Coherent flash imaging will also open up new avenues for structural studies on nano- and microcrystalline substances. This paper addresses the theoretical potentials and limitations of nanocrystallography with extremely intense coherent X-ray pulses. We use urea nanocrystals as a model for generic biological substances and simulate the primary and secondary ionization dynamics in the crystalline sample. The results establish conditions for ultrafast single-shot nanocrystallography diffraction experiments as a function of X-ray fluence, pulse duration, and the size of nanocrystals. Nanocrystallography using ultrafast X-ray pulses has the potential to open up a new route in protein crystallography to solve atomic structures of many systems that remain inaccessible using conventional X-ray sources.

PACS 71.20.Rv -Electron density of states and band structure of crystalline solids -Polymers and organic compounds PACS 79.20.Hx -Electron and ion emission by liquids and solids; impact phenomena -Electron impact: secondary emissionAbstract. -Radiation damage is an unavoidable process when performing structural investigations of biological macromolecules with X-rays. In crystallography this process can be limited through damage distribution in a crystal, while for single molecular imaging it can be outrun by employing short intense pulses. Secondary electron generation is crucial during damage formation and we present a study of urea, as model for biomaterial. From first principles we calculate the band structure and energy loss function, and subsequently the inelastic electron cross section in urea. Using Molecular Dynamics simulations, we quantify the damage and study the magnitude and spatial extent of the electron cloud coming from an incident electron, as well as the dependence with initial energy.

Abstract. -Radiation damage is an unavoidable process when performing structural investigations of biological macromolecules with X-rays. In crystallography this process can be limited through damage distribution in a crystal, while for single molecular imaging it can be outrun by employing short intense pulses. Secondary electron generation is crucial during damage formation and we present a study of urea, as model for biomaterial. From first principles we calculate the band structure and energy loss function, and subsequently the inelastic electron cross section in urea. Using Molecular Dynamics simulations, we quantify the damage and study the magnitude and spatial extent of the electron cloud coming from an incident electron, as well as the dependence with initial energy.

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